---

.Industrial Ecology and Global Change

Edited by

R. SOCOLOW, C. ANDREV/S, F. BERKHOUT, andV. THOMAS

14

Roles for Biomass Energy in SustainableDevelopment v

Robert Williams

.

8..:::1... CAMB RID G E Reproduced with permission from Cambridge University Press.:., UNIVERSITY PRESS..

J,i

--- -

.

.Contents ,t\~f,iJ{:'3;JluM A :2msCf 11

lrroi~4~~l\~1 i"I)M i

""---3 n.~ ::?Jj;t;nl..,r.lfl0 2~:)'

..'"-" ~I101?;2im3 ::bi

Foreword xiii

William MoomawPreface xv

Robert SocolowAcknowledgments xxi

Contributors xxiii

OVERVIEW1. Six Perspectives from Industrial Ecology 3

Robert Socolow

PART 1: VULNERABILITY AND ADAPTATION

2. Introduction 19

The Editors3. Industrial Ecology: Definition and Implementation 23

Thomas Graedel4. Industrialization as a Historical Phenomenon 43

Arnulf Griibler5. Changing Perceptions of Vulnerability 69

Robin Cantor and Steve Rayner6. The Human Dimension of Vulnerability 85

Robert S. Chen7. Global Industrialization: A Developing Country Perspective 107

Saleemul HuqPART 2: THE GRAND CYCLES: DISRUPTION AND REPAIR

8. Introduction 117

The editors9. Human Impacts on the Carbon and Nitrogen Cycles 121

Robert U. Ayres. William H. Schlesinger; and Robert H. Socolow

IX

Contents

10. Charting Development Paths: A Multicountry Comparison of 157

Carbon Dioxide EmissionsWilliam Moomaw and Mark Tullis

11. Reducing Urban Sources of Methane: An Experiment in 173

Industrial EcologyRobert Harriss

12. Reducing Carbon Dioxide Emissions in Russia 183

furi Kononov13. Energy Efficiency in China: Past Experience and Future Prospects 193

.Jiang Zhenping14. Roles for Biomass Energy in Sustainable Development 199

Robert 'Williams

PART 3: TOXICS AND THE ENVIRONl\lmNT

15. Introduction 229

The editors16. Soil as a Vulnerable Environmental System 233

Jerald Schnoor and Valerie Thomas17. The Vulnerability of Biotic Diversity 245

'William Schlesinger18. Global Ecotoxicology: Management and Science 261

Susan Anderson19. Industrial Activity and Metals Emissions 277

Jerome Nriagu20. Metals Loading of the Environment: Cadmium in the Rhine Basin 287

William Stigliani, Peter Jaffe, and Stefan Anderberg21. Emissions and Exposure to Metals: Cadmium aJ:1d Lead 297

Valerie Thomas and Thomas Spiro22. Nuclear Power: An Industrial Ecology that Failed? 319

Frans Berkhout

PART 4: INDUSTRIAL ECOLOGY IN FIRMS

23. Introduction 331

The Editors24. Product Life-Cycle Management to Replace Waste Management 335

Michael Braungart25. Industrial Ecology in the Manufacturing of Consumer Products 339

Wayne France and Valerie Thomas26. Design for Environment: A Management Perspective 349

Bruce Paton27. Prioritizing Impacts in Industrial Ecology 359

Thomas Graedel, Inge Horkeby, and Victoria Norberg-Bohm28. Finding and Implementing Projects that Reduce Waste 371

Kenneth Nelson

-

Contents

" 29. Free-Lunch Economics for Industrial Ecologists 383

Theodore Panayotou and Clifford Zinnes

PART 5: INDUSTRIAL ECOLOGY IN POLICY-MAKING

30. Introduction 401The Editors

31. Policies to Encourage Clean Technology 405

Clinton Andrews32. Initiatives in Lower Saxony to Link Ecology to Economy .423

Monika Griefahn33. Military-to-Civilian Conversion and the Environment in Russia 429

George Golitsyn34. The Political Economy of Raw Materials Extraction and Trade 437

Stephen Bunker35. Development, Environment, and Energy Efficiency 451

Ashok Gadgil

END PIECE

36. The Industrial Ecology Agenda 469

Clinton Andrews, Frans Berkhout, and Valerie Thomas. Organizing Committee Members 478

Working Groups -.: 479

Index 481

--,

-

14

Roles for Biomass Energy in SustainableDevelopment

Robert Williams

Abstract

Advanced technologies such as gasifier/gas turbine systems for electric powergeneration and fuel cells for transportation make it possible for biomass to providea substantial share of world energy in the decades ahead, at competitive costs.While biomass energy industries are being launched today using biomass residuesof agricultural and forest product industries, the largest potential supplies of bio-mass will come from plantations dedicated to biomass energy crops. In industrial-ized countries these plantations will be established primarily on surplus agricul-tural lands, providing a new source of livelihood for farmers and making itpossible eventually to phase out agricultural subsidies. The most promising sitesfor biomass plantations in developing countries are degraded lands that can berevegetated. For developing countries, biomass energy offers an opportunity topromote rural development.

Biomass energy grown sustainably and used to displace fossil fuels can lead tomajor reductions in carbon dioxide emissions at zero incremental cost, as well asgreatly reduced local air pollution through the use of advanced energy conversionand end-use technologies. The growing of biomass energy crops can be eitherdetrimental or beneficial to the environment, depending on how it is done. .Biomass energy systems offer much more flexibility to design plantations that are .

compatible with environmental goals than is possible with the growing of biomassfor food and industrial fiber markets. The~e is time to develop and put into placeenvironmental guidelines to ensure that the growing of bi9mass is carried out inenvironmentally desirable ways, before a biomass energy 'industry becomes wellestablished.

IntroductionBiomass (plant matter) has been used as fuel for millennia. In the 18th and 19thcenturies it was widely used in households, industry, and transportation. .In. theUnited States, as late as 1854, charcoal still accounted for nearly half of pIg Ironproduction. and throughout the antebellum period wood was the dominant fuel for

199

The Grand Cycles

both steamboats and railroads (Williams. 1989). Biomass dominated global energyconsumption through the middle of the 19th century (Davis, 1990). Since then bio-mass has accounted for a diminishing share of world energy, as coal and later oiland natural gas accounted for most of the growth in global energy demand. Todaybiomass is not much used by industry, though it is still widely used for domesticapplications in developing countries--especially in rural areas (Hall et ai., 1993).Still, biomass accounts for about 15% of global energy use, only slightly less thanthe share of global energy accounted for by natural gas (see Figure 1).

Although the trend has been away from biomass as an energy source, there are

strong reasons for revisiting biomass energy:

.Dependence on gasoline and diesel for transport fuels has led to urban air pollu-tion problems in many areas that cannot be solved simply by mandating furthermarginal reductions in tailpipe emissions. California has adopted a policy man-dating the phased introduction of low- and zero-emission transport vehicle/fuelsystems. Other jurisdictions are likely to pursue similar policies (Wald, 1992),and in fact 12 eastern U.S. states in 1994 collectively asked the U.S.Environmental Protection Agency to impose the California regulations on them(Wald, 1994). Some biomass-based transport energy options could effectivelyaddress this challenge (Johansson et ai., 1993; Williams, 1994).

.The prospect of declining future production of conventional oil in most regions

.outside the Middle East (Masters et al., 1990) once more raises concerns aboutthe security of oil supplies. Auid fuels derived from biomass substituted forimported oil can help reduce energy security risks (Johansson et ai., 1993).

.Responding to concerns about global warming may require sharp reductions inthe use of fossil fuels (IPCC, 1990). Biomass grown sustainably and used as afossil fuel substitute will lead to no net buildup in atmospheric carbon dioxide,because the CO2 released in combustion is compensated for by the CO2

extracted from the atmosphere during photosynthesis...A major challenge facing developing countries is to find ways to promote rural

industrialization and rural employment generation, to help curb unsustainableurban migration (Goldemberg et ai., 1988, 1987). Low-cost energy derived'from biomass sources could support such activities (Johansson et al., 1993).

.There are large amounts of deforested and .9therwise degraded lands in tropicaland subtropical regions in need of restoration (Grainger, 1988). Some of theselands could be restored by establishing biomass energy plantations on them.Part of the revenues from the sale of biomass produced on such lands could beused to help pay for these land restoration efforts (Hall et al., 1993; Johansson et

al., 1993)..In industrialized countries, efforts to provide food price and fanner income sta-

bility in the face of growing foodcrop productivities has led to a system of large-scale agricultural subsidies. Despite mounting economic pressures to reduce oreliminate such subsidies, so doing is difficult politically (OECD, 1992).However, converting excess agricultural lands to biomass production for energy

200 .

-~--~~ -

R. 'Williams: Roles for Biomass Energy

s,17.4%

Oil,341% clear,4.1%

World Hydro, 5.5%total = 373 exajoulespopulation = 4.87 billionenergy use per capita = 77 gigajoules

ss, 14.7%

Coal,24.1%

Natural gas, 22.7%

ear, 5.9%

Industrialized Countriestotal = 247 exajoules Hydro, 5.7%(66 percent of world total)

population = 1.22 billion 0(25 percent of wo!ld total) Oil, 38.3% Biomass, 2.8'10

energy use per capita = 202 glga)oules

4.5%

Oil,258%

tural gas, 7.1%Developing Countriestotal = 126 exajoules Nuclear, 0.6%(34 percent of world total) Coal 23 4% Hydro, 5. 1 % .population = 3.65 billion ' ..(75 percent of world total)

energy use per capita = 35 gigajoules .

.mass,38.1%

Figure I. World primary energy consumption by energy source and by world region. Primary energyconsumption is shown for the world (top), industrialized countries (middle), and developing coun-tries (bottom) in 1985. Data from all energy sources except biomass ~ from Johansson er al.(1993). Biomass energy data ~ estimates based on surveys. from Hall et al. (1993).

The primary energy associated with electricity produced from nuclear and hydroelectric sources isassumed to be the equivalent amount of fuel required to produce that electricity, assuming theaverage heat rate (in MJ per kWh) for all fuel-fired power-generating units.

201

The Grand C}'cIes

would provide both a new livelihood for fanners and an opportunity to phaseout such subsidies (Hall el al., 1993; Johansson et al., 1993).

Such considerations, taken together with the good prospects for providing com-petitive energy supplies from biomass using modem energy conversion technolo-gies, led a recent study exploring the prospects for renewable energy to project thatbiomass can have major roles as a renewable energy source (Johansson et al.,

.1993). In a renewables-intensive global energy scenario constructed for that studyit was estimated that renewable energy could provide about 45% of global primaryenergy requirements in 2025 and 57% in 2050, with biomass accounting for about65% of total renewable energy in both years (see Figure 2). For the United States,the corresponding renewable energy shares of total primary energy were projectedto be similar to the renewable shares at the global level, with biomass accountingfor 55-60% of total renewable energy in this period (see Figure 3). In this scenario,biomass supplies are provided mainly by biomass residues of ongoing agriculturaland forest product indusu-y activities (e.g., sugar cane residues and mill and loggingresidues of the pulp and paper indusu-y) and by feedstocks grown on plantationsdedicated to the production of biomass for energy. The present analysis, is focusedon plantation biomass, which accounts for about three-fifths of global biomass sup-plies in this scenario in the period 2025-50 (Johansson et aI., 1993).

.The Challenges Posed by Biomass Energy

The notion of shifting back to biomass for energy flies in the face of conventionalwisdom. Bringing about such a shift would require overcoming strong beliefs heldby many people that biomass is inherently unpromising as an energy supplysource. It is widely believed that:

.Biomass is an inconvenient energy carrier and thus unattractive for modem

energy systems..The use of land to grow biomass for energy conflicts with land needs for food

production..Large-scale production of biomass for energy would create environmental dis-

asters..The energy balances associated with biomass production for energy are unfa-

vorable. .-

.Biomass energy is inherently more costly than fossil fuel energy.

.Resource constraints will limit biomass to a minor role in a modem global

energy system.

In what follows each of these concerns is dealt with in turn.

Attracting Consumer Interest by Modernizing Biomass Energy

Biomass is often called "the poor man's oil" (Goldemberg el al., 1988, 1987). Thischaracterization arises in part from the low bulk density of biomass fuels. Freshly

202

-

R. Williams: Roles for Biomass Energy

70 () = CO2 emISSions (relative to 1985 = 100)

60(744)

50 (881)

.. ~ ~ ~>~CI 40- ,..~ I -,..~ -c -..~~"3oa .~ 3E ~

-; OJa-

20

1

1985 2025 2050

year

.coalgoil~ natural gas&1 nuclear!;:;j hydro and geothermal

0 biomass~ intermittent renewablesms H2 from intermittent renewables

Figure 2. Global primary energy requirements for a renewables-intensive global energy scenario.This figure shows global primary energy requirements for the renew ables-intensive global energyscenario developed in Johansson et ai. (1993) in an exercise carried out to indicate the futureprospects for renewable energy for each of 11 world regions. In developing this scenario, the higheconomic groWth/high energy efficiency demand projections for solid, liquid, and gaseous fuels andelectricity developed by the Response Strategies Working Group of the Intergovernmental Panel onClimate Change (Response Strategies Working Group of the Intergovernmental Panel on ClimateChange, 1990) were adopted in Johansson et ai. (1993) for each world region. For each region a mixof renewable and conventional energy supplies was constructed in Johansson et ai. (1993) to matchthese demand levels, ta.king into account relative energy prices, regional endowments of conven-tional and renewable energy sources, and environmental constraints.

The primary energy associated with electricity produced from nuclear, hydroelectric, geothermal,photovoltaic, wind, and solar thermal-electric sources is assumed to be the equivalent amount of fuelrequired to produce that electricity, assuming the average heat rate (in MJ per kWh) for all fuel-firedpower-generating units in a given year. This global average heat rate is 8.05 MJ per kWh in 2025 and6.65 MJ per kWh in 2050.

For biomass-derived liquid and gaseous fuels the primary energy is the energy content of the bio-mass feedstocks delivered to the biomass energy conversion facilities.

Primary energy consumption in 1985 includes 50 EJ of noncommercial biomass energy (Hall etai., 1993). It is assumed that there is no noncommercial energy use in 2025 and 2050.

203

-

The Grand Cycles

100 () CO2 ~mlsslons (relative to 1985 K 100)

90

t"-J (100)80 i I

l = (394)~~~~~. ' " '

70 , , , , """"II ""'" (255)=... ""' j~ i 60 '" " ,>0 "",DI ' , , , , '

J..'" "",II~ """; ~ 50~-~ ~ '.'.'.' ,..'.'.','E ~~ 40 ...", "C CIJ

Co , , , , , , ,. ..30 "'" ..".,.".., , , , , , ',' ..' '.' ,"'"""""'"20 " , ","'"""""'"

10

01985 2025 2050

year

.coalgoil~ natural gas&1 nuclearm hydro and geothermal

0 biomass~ intermittent renewables~ H2 from intermittent renewables

Figure 3. Primary energy requirements for the United States in a renewables-intensive global energyscenario. This figure shows primary energy ~uirements for the United States in the renewables-intensive global energy scenario developed in Johansson et at. (1993) in an exercise carried out toindicate the futUre prospects for renewable energy for each of II world regions, one of which is theUnited States. In developing this scenario, the high economic growth/high energy efficiency demandprojections for solid, liquid, and gaseous fuels and electricity developed by the Response Sb'ategiesWorking Group of the Intergoven:lmental Panel on Climate Change (1990) were adopted inJohansson et aI. (1993). For the United States and other industrialized countries, this demand sce-nario involves a slow decline in primary energy demand'as the economy expands, as a result of theemphasis given to improved energy efficiency. The mix of renewable and conventional energy sup-plies shown was constrUcted in Johansson et a1. (1993) to match these demand levels, taking intoaccount relative energy prices, endowments of conventional and renewable energy sources, and

environmental consn-aints.The primary energy associated with electricity produced from nuclear, hydroelectric, geothermal,

photovoltaic, wind, and solar thermal-electric sources is assumed to be equivalent to the amount offuel required to produce that electricity, assuming the average heat rate (in MJ per kWh) for all fuel-fired power-generating units in a given year. The U.S. average heat rate is 8.07 MJ per kWh in 2025and 6.42 MJ per kWh in 2050.

For biomass-derived liquid and gaseous fuels the primary energy is the energy content of the bio-mass feedstocks delivered to the biomass energy conversion facilities.

204

c-

R. Williams: Roles for Biomass Energy

cut wood typically has an energy density of about 10 GJ per tonne-comparedwith 25-30 GJ per tonne for various coals and more than 40 GJ per tonne for oil; itis thus both difficult and costly to transport biomass fuels long distances; in ruralareas of developing countries women and children spend considerable time gath-ering fuelwood for cooking. Wood cookstoves also pollute-generating in ruralkitchens of developing countries total suspended particulates, benzo-a-pyren~s,and other pollutants--often at levels far in excess of ambient air quality standards(Smith and Thomeloe, 1992).

As incomes rise, consumer preferences shift toward energy carriers of higherquality. The higher the quality of the fuel, the more convenient is its use and theless pollution is generated. This phenomenon is well-known in cooking fuels:charcoal is preferred to wood, kerosene is preferred to charcoal, and clean gaseousfuels such as liquid petroleum gas (LPG) are preferred to kerosene. This "energyladder" is often invoked to show that consumers will shift away from biomassfuels as their incomes rise. For instance, data show that biomass accounts for 38%of energy use in developing countries (used mostly by poor people in rural areas),but just 3% of energy use in industrialized countries (see Figure 1).

However, with modem technologies, biomass can be converted into liquid orgaseous fuels or into electricity, in cost-effective ways. It is in these forms that bio-mass becomes an acceptable energy source at high-income levels.

Addressing the Food Vs. Fuel Controversy

The renewables-intensive global energy scenario developed in Johansson et al.(1993) calls for establishing worldwide some 400 million hectares of biomassplantations for energy by the second quarter of the 21st century-a land area thatis not small compared with the nearly 1500 million hectares now in cropland(WRI, 1992). Because the world population is expected to nearly double by thattime, the potential for conflict between biomass production for food and biomassproduction for energy warrants careful scrutiny. Because land is needed to growfood, but energy can be provided in many ways, food production should have pri- .ority. The key questions are: How much land is needed for food production? Andhow does this need compare with the arable land resource? In addressing thesequestions it is useful to consider the industrialized and developing country situa-tions separately. .

Industrialized Countries

Because their population growth is slow and food yields have been increasing, theamount of land needed for food production is declining in industrialized countries.

In the United States, more than one-fifth of total cropland, some 33 millionhectares, was idled in 1990, either to keep food prices high or to control erosion.The U.S. Department of Agriculture forecasts that an area of over 50 millionhectares may be idle by 2030 as a result of rising crop yields. despite an expected

205

<:

The Grand C)'cles

doubling of exports of com, wheat, and soybeans (Soil Conservation Service,1989). The urgency of addressing the challenge of excess agricultural lands wasthe major theme of the 1987 repon of The New Farm and Forest Products TaskForce to the Secretary of Agriculture:

The productive capacity of U.S. agriculture is greatly underutilized. Thecountry today has carryover stocks of between six months and one years pro-duction of major commodities, with productivity continuing to increase at afaster rate than demand. Estimates of land in excess of production needs tomeet both domestic and expon market demand range as high as 150 millionacres [61 million hectares]-with about one-third of that already availablefrom the Conservation Reserve Program. This represents an enormouslywasted national asset which, if transformed into a more productive onethrough new products, would have a profoundly positive impact on theNation's economy.

In the European Union more than 15 million hectares of land will have to betaken out of farming by the year 2000, if surpluses and subsidies associated withthe Common Agricultural Policy are to be brought under control (Hummel, 1988).By 2015, according to a Dutch study, the land needed for food production in thecommunity could be 50 to 100 million hectares less than at present (NetherlandsScientific Council for Government Policy, 1992). In the United States and theEuropean Union together, therefore, 100 million hectares of farmland or morecould be idle by the second decade of the next century, which is more than one-third of the total land dedicated to agricultural production today.

While the conversion of excess cropland in the industrialized countries to energyplantations presents an opportunity to make productive use of these lands, such aconversion cannot be easily accomplished under the present policies. In many coun-tries farmers are deterred by a subsidy system that specifies what crops the farmercan produce in order to qualify for a subsidy; and energy crops are not allowed.

In 1991 this subsidy system transferred about $320 billion to farmers (170 bil-lion in Western Europe, 80 billion in the United States, 60 billion in Japan, and 10 .billion in Canada, in current U.S. dollars [OECD, 1992]). These subsidies,amounting to almost $400 per. capita for the 800 million people living in the coun-tries of the Organization of Economic CooP.eration and Development. actuallyrose between 1987 and 1991, in spite of serious political efforts to reverse the tide(see Table 1). The calculation of these subsidies combines costs to consumers inthe form of higher food prices (about $200 billion) and direct payments to farmersfrom taxpayer revenue (about $140 billion), and subtracts revenues from tariffs(about $20 billion). The $80 billion subsidy in the United States is about one-fifthof the total retail expenditure on energy sources in the United States (EnergyInformation Administration, 1991).

Gradual conversion of surplus cropland to profitable biomass energy productionwould make it possible to phase out many of these subsidies. As long as a systemof subsidies continues, however, the bias against energy crops should be removed.

206

;:;;~i\ -

R. Williams: Roles for Biomass Energy

Table 1: Subsidies to agricultural producers in OECD countries (current dollars)

Total Transfers ($ billions) Per Capita Transfers ($)

1987 1991 1987 1991

Western Europe 139 166 390 440EU(12countries)1 119 142 370 410Non-EU (5 countries)2 20 24 630 740

U.S. 813 81 330 320Japan 66 63 540 510Canada 9 10 340 350Australia and New Zealand I I 40 60

Total OECD 295 321 360 380

I European Union countries: Belgium, Denmark, France, Germany, Ireland. Italy, Luxembourg,

Netherlands, United Kingdom, Spain, Greece, and PortUgal.2 Non-European Union countries: Austria, Finland, Norway. Sweden, and Switzerland.3 For comparison. U.S. retail expenditures on energy were $394 billion in 1987 (Energy

Information Administration, 1991).

From OECD, 1992.

Developing Countries

For developing countries the situation is quite different. Because of expected pop-ulation growth and rising incomes, it is likely that more land will be needed forfood production, The Response Strategies Working Group of theIntergovernmental Panel on Climate Change has projected that the land in foodproduction in developing countries will increase 50% by 2025 from the presentlevel of about 700 million hectares (see Table 2) (IPCC, 1991). The demand can becompared to potential supply-that is, land physically capable of supporting eco-nomic crop production, within soil and water constraints, For 91 developing coun-tries, potential cropland was estimated to be about 2000 million hectares-nearly "

three times present cropland (see Table 2) (F:AO, 1991).Looking to the year 2025 and assuming cropland requir~ments in developing

countries increase 50% by then, there would still be a substantial surplus of poten-tial cropland of nearly 1000 million hectares in these countries (see Table 2).There would be substantial regional differences, however, with major surplusestotaling more than 1100 million hectares in Latin America and Africa, and a 110million hectare deficit in Asia. (China was not included in the U.N, Food andAgricultural Organization [FAO] analysis.) Thus it appears that substantialamounts of land suitable for energy plantations may be available in both LatinAmerica and sub-Saharan Africa, even with major expansions of cropland to feedthe growing population. But in Asia, with its high population density, conflicts

with food production could become significant.

207

1

~ -

The Grand Cy'cles

Table 2: Present] and potential2 cropland for 91 developing countries (million

hectares)

Potential Cropland

Present Low Uncertain Good Natural ProblemRegion Cropland Rainfall Rainfall Rainfall flooded Land Desert Total

!. Central America 38 2.2 13 19 507 31 3.5 75f South America 142 26 38 150 106 493 2.8 815

Africa 179 73 97 149 71 358 3.8 753Asia (excl. China) 348 60 67 67 81 118 20 413TouU 706 161 215 386 263 1000 30 2055

I From WRI, 199202 As estimated by the U.N. Food and Agriculture Organization (FAO) in 1990 (FAO, 1991).

Potential cropland is defined by the FAO as all land that is physically capable of economic cropproduction. within soil and water constraints. It excludes land that is too steep or too dry or having

unsuitable soils.

The extent of conflict with food production depends on future food crop produc-tivities. Waggoner (1994) aruges that with feasible productivity gains a world pop-ulation of 10 billion could be supported with no increase in cropland. Assessmentsate needed, country by country, to better understand the prospects for productivitygains and thereby the avoidance of food/fuel conflict.

Unfortunately, the FAa study does not clarify where new cropland would comefrom. To be sure, some forestlands are involved. Clearly. it would not be desirableto cut down virgin forests in favor of intensively managed biomass plantations.Cutting down virgin forests could be avoided, however, by targeting for biomassplantations lands that are deforested or otherwise degraded and that are suitablefor reforestation. One estimate is that over 2000 million hectares of tropical landshave been degraded, of which about 600 million hectares are judged suitable for

reforestation (see Table 3).Outside of Asia the amount of degraded land suitable for reforestation (exclud-

ing degraded lands in the deser.tified drylands category), is substantial (see Table 3)-some 112 million hectares in Latin Americ~.and 62 million hectares in Africa.In Asia, such land areas are also large-some 115 million hectares; however, forAsia, country-by-country assessments are needed to determine the extent to whichits degraded lands will be needed for food production or other purposes warrantinghigher priority than energy.

The main technical challenge of restoration is to find a sequence of plantingsthat can restore ground temperatures, organic and nutrient content, moisture lev-els, and other soil conditions to a point where crop yields are high and sustainable.Successful restoration strategies typically begin by establishing a hardy specieswith the aid of commercial fertilizers or local compost. Once erosion is stabilizedand ground temperatUres lowered, organic material can accumulate, microbes can

208

~

,..

R. Williams: Roles for Biomass Energy

Table 3: Geographical distribution of tropical degraded lands and potential areas

for reforestation (million hectares)

Logged Forest Deforested DesertifiedRegion Forests Fallows Watersheds Dry1ands Total

Latin America 44 85 27 162 318Africa 39 59 3 741 842Asia 54 59 56 748 917Total 137 203 87 1650 2077Area suitable for -203 87 331 621

reforestation

From Grainger. 1988. 1990.

return, and moisture and nutrient properties can be steadily improved (OTA, 1992;Parham etal., 1993).

If it is feasible to overcome this technical challenge and various other socioeco-nomic, political, and cultural challenges (Hall et al., 1993), plantation biomass indeveloping regions could make substantial contributions to world energy withoutserious conflict with food production. In sub-Saharan Africa and Latin America,where potential land areas for plantations are especially large, biomass could beproduced by the second quarter of the 21st century in quantities large enough tomake these regions major exporters of biomass-derived liquid fuels, offering com-petition to oil exporters and bringing price stability to the global liquid fuels mar-ket (Johansson et al., 1993). A possible interregional fuels trade scenario for 2050is shown in Figure 4.

Converting such large areas of degraded lands to successful commercial planta-tions would be a formidable task. Research is needed to identify the most promis-ing restoration techniques for all the different land types and conditions involved.Yet the fact that many of the successful plantations in developing countries havebeen established on degraded lands (Hall et al., 1993) suggests that it may be fea-sible to deal with these challenges with adequate research and commitment. Andinterest in restoring tropical degraded lands is high, as indicated by the ambitiousglobal net afforestation goal of 12 million hectares per year by the year 2000 setforth in the Noordwijk Declaration at the 1989 Ministerial Conference onAtmospheric and Climate Change in Noordwijk, The Netherlands (MinisterialConference on Atmospheric Climatic Change, 1989).

Making Biomass Production for Energy Environmentally Attractive

Throughout the 19th and 20th centuries, there has been substantial deforestationworldwide, as a result of both land clearing for agriculture and nonsustainablemining of the forests for forest products. These cleared lands cannot supportthe diversity of species that once flourished there. Moreover, modem intensiveagricultural management practices have created other serious environmental

209

The Grand Cycles

other. 4 7%Former Centrally Planned Europe. 2.7%

South and East Asia, 34%

other, 12.5%

Middle East, 44%

Latin America, 12 6%

Africa. 20%

198518.6 million barrels per day of oil-equivalent

NorthernAfrica, 2.9%

Middle East, 28.8%

Middle East, 28.9%

Canada, 0.9%

n Africa, 20.2%

latin America.~ solar hydrogen 7.2%0 methanol from biomass

g oil 2050~ natural gas 32.3 million barrels per day of oil-equivalent

Figure 4. Fuel exports by region for a renew ables-intensive global energy scenario. The imponanceof world energy commerce for the renewables-intensive global energy scenario developed inJohansson et aI. (1993) and for which global primary energy consumption is shown in Figure 2 isillustrated here. The figures show that by the middle of the next century there would be comparableexports of oil, natural gas, and biomass-derived methanol, as well as small exports of hydrogenderived from renewable sources. This diversified export mix is in sharp contrast to the situation

today, where oil dominates international commerce in liquid and gaseous fuels.Most methanol exports would originate in sub-Saharan Africa and in Latin America, where there

are vast degraded areas suitable for revegetation that will not be needed for cropland (see Tables 2and 3). Growing biomass on such lands as feedstocks for producing methanol (or other biomass

fuels) would provide a powerful economic driver for restoring these lands.

210

;';.");; -

R. Williams: Roies for Biomass Energy

problems. including loss of soil quality, erosion, and contamination of runoff withnitrates and other chemicals arising from the use of fertilizers, herbicides, and pes-ticides. A major concern is that such problems would be aggravated by a majorshift to biomass energy.

There is no doubt that biomass can be grown for energy purposes in ways thatare environmentally undesirable. However, it is also possible to improve the landenvironmentally through the production of biomass for energy. The environmentalou[come depends sensitively on how and where the biomass is produced.

Consider first the challenge of sustaining the productivity of the land. Since theharvesting of biomass removes nutrients from the site, care must be taken toensure that these nutrients are restored. This challenge can be dealt with for energyplantations more easily than for agriculture, largely because the choice amongplants is more flexible, so that choices can be better targeted to environmentalobjectives. This is especially tt1le for biomass conversion technologies that beginwith thennochemical gasification (which will often be the preferred approach forproviding modem energy carriers from biomass [Johansson et ai., 1993]).

With thennochemical gasification it is feasible to recover all mineral nutrientsas ash at the biomass conversion facility and to return the ash to the plantation sitefor use as fertilizer. By contrast, fixed nitrogen is lost to the atmosphere at the con-version facility, but it can be replenished in several environmentally acceptableways. First, when trees are the harvested crop, the leaves, twigs, and smallbranches, in which nutrients are concentrated, can be left at the site to reducenutrient loss. (So doing also helps maintain soil quality and reduce erosionthrough the addition of organic matter to the soil.) Also, nitrogen-fixing speciescan be selected for the plantation or for interplanting with the primary plantationspecies to eliminate or reduce to low levels the need for artificial fertilizer inputs.The promise of intercropping strategies is suggested by 10-year trials in Hawaii,where yields of 25 dry tonnes per hectare per year were achieved without nitrogenfertilizer when Eucalyptus was interplanted with nitrogen-fixing Albizia (DeBellet ai., 1989).

Energy crops also offer flexibility in dealing with erosion and with chemical .

pollution fro,m herbicide use. These problems occur mainly at the time of cropestablishment. Accordingly, if the energy crop is an annual crop (e.g., sweetsorghum), the erosion and herbicide pollution problelI}s would be similar to thosefor annual row-crop agriculture. The cultivation of such crops should be avoidedon erodable lands. However, the choices for biomass energy crops also includefast-growing trees that are harvested only every 5 to 8 years and replanted perhapsevery 15 to 24 years, and perennial grasses that are harvested annually butreplanted perhaps only once in a decade. In both cases erosion would be sharplyreduced, on average, as would the need for herbicides.

A major concern about agriculture is water pollution from nitrate runoff associ-ated with the excessive use of nitrate fertilizers. Where it would not be possible todeal with this problem by planting nitrogen-fixing plantation species as an alterna-

tive to chemical fertilizers, runoff could be controlled by planting fast-growing

211

The Grand Cycles

trees in riparian zones (see Schnoor and Thomas, this volume). In the future it willalso be possible to use "designer fertilizers" whose release is timed to match the

temporal variations of the plant's demand for fertilizer (Linder, 1989; Kimmins,1990).

Another concern is chemica1 pollution from the use of pesticides to control theplantation crop against attack by pests and pathogens. While plantations in thetropics and subtropics tend to be more affected by disease and pest epidemics thanthose in temperate regions, experience with plantations in these regions shows thatcareful selection of species and good plantation design and management can behelpful in controlling pests and diseases, rendering the use of chemical pesticidesunnecessary in all but extraordinary circumstances. A good plantation design, forexample, will include: (1) areas set aside for native flora and fauna to harbor nat-ura1 predators for plantation pest control, and perhaps (2) blocks of crops charac-terized by different clones and/or species. If a pest attack breaks out on one block,a now common practice in well-managed plantations is to let the attack run itscourse and to let predators from the set-aside areas help ha1t the pest outbreak

(Hall eta/., 1993).Biomass plantations are often criticized because the range of biological species

they support is much narrower than for natural forests. But if biomass plantationswere established on degraded lands, the result could be a net improvement in eco-10gica1 diversity. Similarly, if biomass energy crops were to replace monoculturalfood crops, in many cases the shift would be to a more complex ecosystem (Beyea

eta/., 1992).Preserving biodiversity will require careful land-use planning. At the plantation

level, as already noted, establishing and maintaining natural reserves can be help-ful in controlling crop pests while providing local ecological benefits. At theregional level, natural forest patches could be connected via a network of undis-turbed corridors (riparian buffer zones, shelterbelts, and hedgerows betweenfields), thus enabling species to migrate from one habitat to another (Beyea et a/.,

1992).

Achieving Favorable ~nergy Balances in Biomass Production forEnergy .For biomass energy systems to be viable, the net energy ba1ance must be favor-able-i.e., the useful energy produced must be greater than the fossil fuel energyinputs required to provide the biomass energy. Concerns about net energy balanceshave been widely voiced in the case of fuel ethanol from maize (corn), which isproduced in the United States under subsidy at a rate of 4 billion liters per year. Inthis case the net energy balance is often marginal, and in some instances, the fossilfuel inputs to the system are greater than the alcohol energy produced (Wyman eta/., 1993). Maize, however, is a feedstock intended primarily for use as food, notfuel, and its production system is more energy-intensive than most other biomass

crops.

212

~

.

R. Williams: Roles for Biomass Energy

Many biomass energy systems have favorable energy balances. For example,

in the production of fuel ethanol from sugar cane in Brazil (where production at

a level of 12 billion liters per year provides nearly one-fifth of total transport

fuel requirements) the energy content of the alcohol is about six times the fossil

fuel inputs required to grow, harvest, and transport the cane and convert it to

alcohol (Goldemberg et al., 1993). The energy balances are also favorable for

many energy plantation crops that might be grown in temperate climates. Table 4

shows that with present plantation technology, the energy contents of hybrid

poplar, sorghum, and switchgrass harvested and hauled 40 km range from 11 to 16

times the fossil fuel energy needed to provide the biomass (Turhollow and

Perlack, 1991). This harvested biomass could be used with near-term technology

to produce methanol at an overall efficiency of nearly 60% (Katofsky, 1993), so

the net energy balance would be 6 to 9 times the fossil fuel input. With improved

yields in the future, these ratios are likely to be still higher (Turhollow and

Perlack, 1991).

Achieving Attractive Economics by Modernizing Biomass Energy

The planting, cultivation, and harvesting of biomass is generally more labor-inten-

sive and costly than recovering coal or other fossil fuels from the ground. Thus,

per unit of contained energy, biomass tends to be the more costly, especially where

there are abundant indigenous fossil fuel resources. Nonetheless, biomass energy

Table 4: Energy balances for biomass production on plantations. 1990 technology

Hybrid Poplar Sorghum Switchgrass

Energy inputs (GJl11ectare)Establishment 0.14 1.3 0.39Fertilizers 3.3 8.9 5.3Herbicides 0.41 1.8 -

Equipment 0.17 --.Harvesting 7.3 3.7 5.5 .

Hauling! 2.4 3.8 2.8Total 13.8 .19.5 13.9

Energy output2 (GJl11ectare) 224 233 ." 158

Energyrati03 16 12 11

1 The energy required to transport the biomass 40 krn to a biomass processing plant.2 Yields net of harvesting and storage losses are assumed to be 11.3 tonnes per hectare per year for

hybrid poplar (with a heating value of 19.8 GJ/tonne), 13.3 tonnes per hectare per year for sorghum(heating value of 17.5 GJ/tonne), and 9.0 tonnes per hectare per year for switchgrass (heating value

of 17.5 GJ/tonne).3 The energy ratio = energy output/energy input.

Reprinted from Turhollow and Perlack. 1991. @ 1991, with kind pem1ission from Elsevier

Science Ltd., The Boulevard, Langford Lane, Kidlington OX5 1GB, U.K.

2t3

--

The Grand C)'cles

systems can be cost-competitive with fossil fuel energy systems. A more meaning-

ful measure of economic performance is the cost of the energy services, takinginto account conversion into electricity and gaseous or liquid fuels, and the sys-tems in which the energy is used. On a cost-of-service basis the economic outlook

for biomass can be favorable if modern conversion and end-use technologies are

used. This is illustrated below first for electricity generated from biomass, and

then for biomass-derived gaseous and liquid fuels for transportation.

Biomass Electricity

Today biomass, mainly in the form of industrial and agricultural residues, is usedto generate electricity with conventional steam-turbine power-generators. These

biomass power systems can be cost-competitive where low-cost biomass fuels areavailable, in spite of the fact that steam-turbine technologies are comparativelyinefficient and capital-intensive at the small sizes required for biomass electricity

production. The United States currently has more than 8000 megawatts of electricgenerating capacity fueled with such feedstocks, most of which was developed in

the 1980s. (For comparison, total U.S. generating capacity is about 700,000megawatts.) Biomass electricity generation using steam turbines will not expand

.much in the future, because unused supplies of low-cost biomass residues are

.rapidly becoming unavailable.Biomass power generation involving the use of more costly but more abundant

feedstocks could be made cost-competitive by adapting advanced-gasification

technologies originally developed for coal for use with gas turbine-based powersystems (Williams and Larson, 1993). Its very low sulfur content gives biomass a

marked advantage over coal for power generation applications. With currentlyavailable sulfur removal technology, coal must be gasified in ,oxygen; the sulfur is

removed from the product gas in a "scrubber" prior to combustion of the gas in thegas turbine. Since biomass has negligible sulfur, it can be gasified in air, thereby

saving the substantial cost of a plant that separates oxygen from air, and expensive.sulfur removal equipment is not needed. Biomass gasifier/gas turbine power sys-

tems with efficiencies of 40o/c or more will be demonstrated in the mid-1990s andwill probably be commercially available by.2000. These systems offer high effi-ciencies and low unit capital costs for baseload power generation at relativelymodest capacity (below 100 megawatts). Electricity from such syst~ms will prob-

ably be able to compete with coal-fired electricity in many circumstances-evenwith relatively costly biomass feedstocks. By 2025, gas turbines may give way toeven more efficient high-temperature fuel cells (Williams and Larson, 1993).

The electric power industry is beginning to appreciate the importance of bio-mass for power generation. In an assessment by the Electric Power Research

Institute of the potential for biomass-based power generation, it is projected that

biomass could be used to support 50,000 megawatts of electric capacity in the

United States by 2010 and probably twice that amount by 2030 (Turnbull, 1993).

214

-~

....

...

R. Williams: Roles for Biomass Energy

Transport Fuels from Biomass

Unlike the auspicious near-tenn outlook for biomass-derived electricity, very largeincreases in the world oil price are required before biomass-derived transport fuelscould compete in cost with gasoline on a cost-per-unit-of-fuel-energy basis.Nevertheless, ongoing changes in the transport sector could pennit biomass fuelsto compete in providing transport services at world oil prices near the present lowlevel. This prospect will be illustrated here for methanol and gaseous hydrogenfuels derived from biomass via thermochemical gasification.

Based on the use of gasification technology that could be commercialized by theturn of the century, it should be feasible to provide the consumer with eithermethanol or hydrogen derived from biomass at a cost that is only 40 to 50% morethan the price of gasoline expected at that time. Moreover, these biomass-derivedfuels are expected to cost no more than the same fuels derived from coal-eventhough the biomass feedstock would be more costly than coal. This surprisingresult is due in part to the fact that costly sulfur cleanup technology is not neededfor biomass and in part to the fact that biomass is more reactive than coal, whichmakes it possible to gasify the biomass at a lower temperature. With either feed-stock the product of gasification is a nitrogen-free synthesis gas (mainly carbonmonoxide and hydrogen, plus some methane) that is subsequently processed toeither methanol or hydrogen. In the case of coal, this synthesis gas is produced bygasification in oxygen; the needed high gasification temperatures are provided bypartial oxidation of some of the coal in the gasifier; as for power generation, thisentails the high cost of a plant to separate oxygen from air. In the case of biomass,gasification can be carried out in steam, with the needed heat provided by an exter-nal combustor; the lower gasification temperatures realizable with such "indirectlyheated" gasifiers are adequate for biomass gasification, thereby obviating the needfor the costly oxygen separation plant (Williams, 1994; Katofsky, 1993).

Synthetic fuels will be needed for transportation, in part to avoid overdepen-dence on insecure sources of foreign oil. U.S. domestic crude oil productionpeaked in 1970; by 1993 production had fallen to 70% of the peak level; by 2030production is expected to be less than 39% of the peak level (Department ofEnergy, 1991). Since biomass-derived synthetic fuels are e~pected to be no morecostly than those derived from coal, they would be preferred in light of the envi-ronmental advantages.

A shift to synthetic fuels will probably be accelerated by air quality concernsposed by the use of the internal combustion engine in transportation. While it hasdominated road transportation since the automobile was introduced. the long-termoutlook for this engine is clouded by growing perceptions that air quality goalscannot be met simply by mandating further incremental reductions in tail-pipeemissions of new vehicles, and that a shift to very-Iow- or zero-emission vehiclesis needed. Already the state of California has mandated that 10% of new cars pur-chased in 2003 must be zero-emission vehicles, and 12 eastern states have agreedto adopt the same requirement (Wald, 1994).

215

---

The Grand Cycle.\"

The California air-quality initiative has led to a substantial industrial effort tocommercialize the battery-powered electric car. While the battery-powered elec-tric car is a zero-emission vehicle, its potential is limited, without major advancesin battery technology that make it feasible to overcome the long (several-hour)recharging time (Johansson et ai., 1993; Williams, 1994).

An alternative is the fuel-cell car operated on compressed hydrogen. As in thebattery-powered electric car, electric motors provide the mechanical power that dri-ves the wheels. But the electricity to run the motors is provided not by a battery butrather by a fuel cell that converts energy stored in compressed hydrogen gas canis-ters directly into electricity. Unlike the battery-powered electric car, the hydrogenfuel-cell car can be refueled in several minutes. Moreover, the life-cycle cost, i.e.,the total cost of owning and operating a fuel-cell car (in cents per kIn) operated onhydrogen derived from biomass is likely to be less than for a battery-powered elec-tric car (Johansson et al., 1993; Williams, 1994; Katofsky, 1993). The life-cyclecost could also be less than for a car with an internal combustion engine of compa-rable perfonnance even though the fuel is expected to be more expensive thangasoline, mainly because the fuel-cell car is expected to be three times as energyefficient and because it is expected to have lower maintenance costs.

A drawback of the hydrogen fuel-cell option is the requirement for an infra-structure for gaseous hydrogen under pressure. An alternative is to use methanol atatmospheric pressure as a hydrogen carrier: the methanol would react with steam

..in a "refonner" under the hood of the car, producing a mixture of carbon dioxideand hydrogen, thereby providing the hydrogen needed to operate the fuel cell. Themain advantages of the methanol option are that it is easier to establish a distribu-tion infrastructure for a liquid fuel than for pressurized hydrogen, and it is easier tostore methanol onboard the car than pressurized hydrogen. The main drawbacksare that a methanol fuel cell vehicle would be more complicated, and it would notqualify as a zero-emission vehicle because of the small amounts of air pollutantsgenerated by the refonner. Lifecycle costs for the methanol and hydrogen fuel cellvehicle options would be comparable (Williams, 1994; Katofsky, 1993).

Fuels derived from biomass are expected to become competitive on a lifecycle .cost basis because both hydrogen and methanol can be readily used in technologi-cally superior fuel-cell vehicles, while gasoline and other hydrocarbon fuelscannot-at least for first-generation fuel-cell vehicles. I Thus biomass-derived

methanol could become a major energy carrier in international commerce in a worldthat is sensitive to environmental values. The world trade pattern for liquid fuels,shown in Figure 4 for a renewables-intensive global energy scenario (Johanssonet al., 1993), shows equal levels of trade for oil and biomass-derived methanol in theperiod 2025-50, based on an assumed indifference between these fuels.

IThe most likely first candidate fuel cell for automotive propulsion is the proton-exchange-membrane fuel cell,which operates at about 100 °C. At such a low temperature it is practical to reform methanol on board the car, but

not other fuels. In the future, if high-temperature fue1 cells (operating at about lOOO°C) become practical forvehicles. it may be feasible to reform a wide range of hydrocarbon or alcohol fuels under the hood of the car.

216

------~c~~-~-~~-

.

..R. Williams: Roles for Biomass Energy

Creating Major Energy Roles for Biomass with Limited LandResources

Because the photosynthetic process is a relatively inefficient way of convertingsolar energy into chemical-fuel energy, large land areas are required if biomass isto make major contributions to energy supply. For example, displacing fossil fuelsin the United States with biomass grown on plantations at the average productivityof U.S. forests (4 dry tonnes per hectare per year) would require an area approxi-mately equal to the total U.S. land area. This suggests that biomass can neverbecome a significant energy source. While there is not enough suitable land toenable biomass to provide all energy needs, the role of biomass can neverthelessbe substantial, if modern technologies are used for biomass production andconversion.

The land constraints on biomass production can be reduced in part by inten-sively managing the biomass plantations. With modern production techniques,biomass productivities far in excess of natural forest yields can be realized. A rea-sonable goal for the average harvestable yield on large-scale plantations in theUnited States is 15 dry tonnes per hectare per year (Hall et al., 1993), correspond-ing to a photosynthetic efficiency of about 0.5%. Assuming that by 2030 theamount of land in the United States committed to biomass plantations is 30 millionhectares-approximately the amount of excess cropland in the United States atpresent-bio'mass production would be about 9 EJ per year, more than 10% of cur-rent U.S. primary energy use (about 80 EJ per year).

The land constraints on biomass production can also be eased by exploiting forenergy purposes urban wastes and residues of the agricultural and forest-productindustries that can be recovered in environmentally accepta.ble ways. It has beenestimated that such residues in the United States could amount to about 6 EJ peryear (Beyea et al., 1992).

The biomass energy potentially available from these two sources, some 15 EJper year, could probably be produced in the United States in environmentallyacceptable ways without confronting significant land-use constraints. This is .

equivalent to about 20% of current U.S. primary energy use, exclusive of biomass.It does not follow, however, that these p~tential biomass supplies would displace20% of conventional U.S. energy. The extent to which conventional energy wouldbe displaced depends sensitively on the conversion technoiogies deployed.

.Consider, for example, the two energy activities often targeted for replacementby biomass energy: the generation of electricity from coal and the running of light-duty vehicles (automobiles and light trucks) on gasoline. In the United States theseactivities accounted in 1987 for some 30 EJ of primary energy and about one-halfof total carbon dioxide emissions from fossil fuel burning. If these two activities(at 1987 activity levels) could be replaced by biomass grown renewably, the resultwould therefore be a 50% reduction in U.S. carbon dioxide emissions. Threeexamples of replacement technologies based on biomass are considered here. The

overall results are displayed in Figure 5.

217

The Grand C.vcles

50

45

40

~ 35E~ ...-I\) 3~ ~Z"...~ CIJ>. Q.

25DI~~-II ~C 0

~.~ 2IVE.;: 1Co

1

actual present near-term advanced potentialfossil fuel biomass

use supply(1987)

biomass required to replacefossil fuel using alternative

technologies

.coal-based power generation

~ light-duty vehicles

0 biomass plantations

~ biomass residues

present: steam-electric power,methanol in internal combustion engine vehicles (1987 fuel economy)

near-term: biomass gasifier/gas turbine power, .

methanol in internal combustion engine vehicles (improved fuel economy)future: biomass gasifier/molten carbonate fuel-cell power,

methanol in proton-exchange-membrane fuel-cell vehicles

Figure 5. Energy for light-<luty vehicles and power generation in the United States. Shown here arethe biomass primary energy requirements for displacing all petroleum used by light-<luty vehicles(automobiles and light trucks) and all coal-fired power generation in the United States. at the 1987activity levels. with alternative biomass technologies. in relation to potential biomass supplies.

The bar on the left shows fuel actually consumed in 1987 by light-<luty vehicles and by coal-firedpower plants. The second bar shows the biomass primary energy requirements if light-duty vehiclesand coal-fired power plants at 1987 activity levels were replaced by biomass energy systems that arecommercially available today. The third bar shows biomass requirements if technologies likely to beavailable in the year 2000+ time frame were used to replace all oil used for light-<luty vehicles and allcoal-based power generation. at 1987 activity levels. The fourth bar shows the biomass requirementsif technologies likely to be widely available in the 2020 time frame were used to replace all oil usedfor light-duty vehicles and all coal-based power generation. at 1987 activity levels. The bar on the

218

,

,

R. Williams: Roles for Biomass Energy

Suppose first that biomass were used with commercially available technologies:(1) replacing coal-based steam-electric power plants with biomass-based steam-electric power plants having a 20% average efficiency, and (2) replacing gasolineby methanol in internal-combustion-engine light-duty vehicles having 1987 aver-age fuel economies, deriving the methanol from biomass (using commerciallyavailable technology designed to make methanol from coal but modified toaccommodate biomass), and assuming no improvement in the fuel economy of thevehicles other than what would be inherent in a shift from gasoline to methanol.The amount of biomass needed annually for this conversion would be about 49 EJper year, 60% more than the amount of fossil fuels now used for these purposesand more than three times the 15 EJ per year of biomass supplies estimated aboveto be potentially available.

Consider, instead, conversion technology likely to be available by the turn ofthe century. The first generation of biomass-integrated gasifier/gas turbine tech-nology will probably be commercially available, making it possible to roughlydouble the efficiency of biomass power generation (WIlliams and Larson, 1993).In this time frame more energy-efficient biomass-to-methanol conversiontechnologies may also become available (Katofsky, 1993). Moreover, it will befeasible and cost-effective to introduce internal combustion engine vehicles oper-ated on methanol having much higher fuel economies. Using these technologiesthe total biomass required to displace all coal-based power generation and all oiluse by light-duty vehicles at 1987 activity levels would be reduced to 24 EJ

per year.During the second decade of next century, a third set of conversion technologies

should be available, including energy-efficient fuel-cell technologies for both sta-tionary electric power generation and motor vehicle applications. For stationarypower applications one may anticipate 57% efficient biomass-integratedgasifier/fuel-cell systems employing molten-carbonate or solid-oxide fuel cells.For motor vehicle applications, one may see proton-exchange-membrane fuel-cellvehicles that are 2.5 times as energy-efficient as comparable gasoline-fired inter-nal-combustion-engine vehicles. Using these technologies the total biomassrequired to displace all coal-based power generation and all oil use by light-dutyvehicles at 1987 activity levels would ~ reduced to about 14 EJ per year, which iscomparable to the above estimate of. potential supplies from plantations andresidues. .

Thus with advanced technologies biomass can play major roles in the energyeconomy, despite the low efficiency of photosynthesis.

Figure 5 contd.right shows potential biomass supplies from plantations on 30 million hectares of excess agriculturallands plus residues (urban refuse plus agricultural and forest product industry residues) that arerecoverable under environmental constraints.

For details see Endnote for Figure 5. at the end of the chapter.

219

-~-,

-~

The Grand Cycles

Conclusion

As a supply option for modem energy economies, biomass is unusual because itsproduction and use would relate to a far wider range of human activities than anyother energy source. This is in part because biomass energy is derived from photo-synthesis, without which human life would not be possible. Biomass for energycould emerge as a human use of photosynthesis that is comparable in scale to that

.for agriculture or forestry.If biomass energy systems are poorly managed. the benefits may not outweigh

the social costs. But if biomass is well managed, it is likely that the major concernspeople have about biomass energy could be addressed. Successfully developed,biomass energy could provide a broad range of environmental, social, and eco-nomic benefits. Worldwide, people could enjoy:

.competitively priced modem energy carriers for a substantial fraction of humanenergy needs. if advanced conversion and end-use technologies are used;

.the opportunity to reduce CO2 emissions at zero incremental cost, through thedisplacement of fossil fuels;2

.fuels that are compatible with zero-emission or near-zero emission fuel-cellvehicles, for combating urban air pollution problems.

.In addition, the worldwide development of a biofuels industry could provideinterfuel competition, energy price stability, and increased energy security in theworld fuels market. In developing countries, biomass energy plantations couldprovide a strong basis for rural development; an opportunity ~o pay for the restora-tion of many subtropical degraded lands through their conversion to biomass plan-tations for energy; and stimulation for economic development in sub-SaharanAfrica and Latin America as they become large-scale biofuels exporters. In indus-trialized countries the development of biomass energy could .benefit the agricul-tural sector by providing a new livelihood for farmers. It would also provideindustrialized countries an opportunity to phase out agricultural subsidies eventu-ally, thereby strengthening the economies of these countries while leveling the .playing field in world trade for farmers in developing countries.

But these benefits cannot be realized without innovative public policies, coordi-nated internationally, designed to launch a new industry. An obvious first stepwould be to eliminate the various national policies biased against biomass energysystems, such as subsidies, tax incentives, and regulations that arc not neutralacross fuels. A coordinated international research and development program will

21n addition. some carbon would be sequestered in the steady-state inventory of biomass plantations. Neglectingchanges in soil carbon associated with establishing plantations and considering only the avenge inventory asso-ciated with biomass that will be harvested, the sequestering capacity would be about 9 billion tonnes of carbon(assuming an average rotation length of six years between cuts). corresponding to ~ years of buildup of car-bon diox.ide in the atmosphere.

220

-~

,,

R. Williams: Roles for Biomass Energy

also be necessary, with two parallel thrusts: (1) sustainable biomass production ina wide range of climates and soils, and (2) innovative, cost-effective energy con-version and end-use technologies. Agreement on environmental guidelines shouldbe sought at an early stage, to give impetus to development and commercializationof options that are environmentally attractive, and to safeguard against undesirableand self-defeating approaches. Resources will have to be transferred from indus-trialized countries to developing countries to assure access to advanced biomassenergy technologies in developing countries.

Five years ago, the required policy changes would have been deemed unrealis-tic, even unthinkable. But today this is no longer the case. A global consensus isemerging that the only acceptable development is sustainable development. Thiswas the underlying theme of the United Nations Conference on Environment andDevelopment in Rio de Janeiro, in June 1992. It is now realized that the only wayto achieve sustainable development is to shift from one-dimensional policy-mak-ing to holistic approaches that deal with all direct and indirect impacts of a giveneconomic activity, making concerted efforts to avoid adverse impacts before theyoccur.

Thus, though it is unfamiliar or at least not yet well understood by most people,biomass energy will receive focused attention in the forthcoming sustainabledevelopment debates-both because of potential disastrous consequences of il1-planned biomass energy developments and because of the enormous overall bene-fits in support of sustainable development goals that would arise from the properdevelopment of biomass energy.

The timing of these debates could not be better for the biomass energy commu-nity. Because modernized biomass energy plays a negligible role in the worldenergy economy at present, the future shape .of the biomass energy industry can bemolded by the sustainable development debates, before the industry becomes wellestablished.

It is a rare event in modern history that the big concerns about potential adverseimpacts of technology are aired before the technology is implemented. And rarerstill is the opportunity to address these concerns by timely changes of course.

AcknowledgmentsThis research was supported by the Office of Energy and'lnfrastructure of the U.S.Agency for International Development, the U.S. Environmental ProtectionAgency's Air and Energy Engineering Laboratory, the Geraldine R. DodgeFoundation, the Energy Foundation, the W. Alton Jones Foundation, the MerckFund, the New Land Foundation, and the Rockefeller Foundation.

References

Beyea. J.. 1. Cook. D. O. Hall, R. H. Socolow, and R.H. Williams. 1992, Toward EcologicalGuidelines for LArge-Scale Biomass Energy Development. Report of a Workshop for Engineers,

221

The Grand CycLes

Ecologists, and Policymakers Convened by the National Audubon Society and PrincetonUniversity, May 6,1991, National Audubon Society, New York.

Davis, G. R. 1990. Energy for planet earth. Scientific American 263(3),54-63.

DeBell, D. S., C. D. Whitesell, and T. H. Schubert. 1989. Using N.,-fixing Albizia to increase growthof eucalyptus plantations in Hawaii. Forest Science 35( 1),64-7-5.

Energy Information Administration. 1991. State Energy Price and Expenditure Report 1989. U.S.Department of Energy, DOFJEIA-0376(89).

FAO (U.N. Food and Agriculture Organization). 1991. Agricultural Land Use: Inventory ofAgroecological Zones Studies. FAO, Rome, Italy.

Goldemberg, J., T. B. Johansson, A. K. N. Reddy, and R. H. Williams. 1987. Energy for aSustainable World. World Resources Institute, Washington, D.C., 119 pp.

Goldemberg, J., T. B. Johansson, A. K. N. Reddy, and R. H. Williams. 1988. Energy for aSustainable World. Wiley-Eastern, Delhi, 517 pp.

Goldemberg, J., L, C. Monaco, and I. Macedo. 1993. The Brazilian fuel-alcohol program. InRenewable Energy: Sources for Fuel and Electricity (T. B. Johansson, H. Kelly, A. K. N. Reddy,and R. H. Williams, eds.), Island Press, Washington, D.C., 841-864.

Grainger, A. 1988. Estimating areas of degraded tropical lands requiring replenishment of forestcover. International Tree Crops JournalS, 31-61.

Grainger, A. 1990. Modelling the impact of alternative afforestation strategies to reduce carbonemissions. In Proceedings of the Intergovernmental Panel on Climate Change Conference onTropical Forestry Response Options to Climate Change, Report No. 20P-2003, Office of PolicyAnalysis, U.S. Environmental Protection Agency, Washington, D.C.

Hall, D.O., F. Rosillo-Calle, R. H. Williams, and J. Woods. 1993. Biomass for energy: Supplyprospects. In Renewable Energy: Sources for Fuel and Electricity (T.B. Johansson, H. Kelly,A. K. N. Reddy, and R. H. Williams, eds.), Island Press, Washington, D.C., 593-652.

Hummel, F. C. 1988. Biomass forestry: Implications for land-use policy in Europe. Land Use Policy,375-384.

IPCC (Intergovernmental Panel on Climate Change). 1990. Climate Change: The IPCC ScientificAss~ssment (J.T Houghton,.G. J. Jenkins, and J. J. Ephraums, eds.), Cambridge University Press,Cambridge, U.K.

IPCC. 1991. Climate Change: The IPCC Response Strategies. Island Press, Washington, D.C.

Johansson, T. B., H. Kelly, A. K. N. Reddy, and R. H. Williams. 1993. Renewable fuels and electric-ity for a growing world economy: Defining and achieving the potential. In Renewable Energy:Sources for Fuel and Electricity (T. B. Johansson, H. Kelly, A. K. N. Reddy, and R. H. Williams,eds.), Island Press, WashingttJn, D.C., 1-72.

Katofsky, R. E. 1993. Production of Fluid Fuels friJm Biomass. PU/CEES Report No. 279, Centerfor Energy and Environmental Studies, Princeton University, Princeton, New Jersey.

Kimmins, J. P. 1990. Modelling the sustainability of forest production and yield for a changing anduncertain future. The Forest Chronicle 6, 271-280.

Linder, S. 1989. Nutrient control of forest yield. In Nutrition of Trees, Marcus WallenbergFoundation Symposia Vol. 6, Falun, Sweden, 62-87.

Masters. C. D., D. H. Root, and E. D. Attanasi. 1990. World oil and gas resources-Future produc-tion realities. Annual Review of Energy 15, 23-31.

Ministerial Conference on Atmospheric and Climatic Change. 1989. The Noordwijk Declaration onAtmospheric Pollution and Climatic Change. Ministerial Conference on Atmospheric andClimatic Change, Noordwijk, Netherlands.

222

,

.'

R. Williams: Roles for Biomass Energy

Netherlands Scientific Council for Government Policy. 1992. Grounds for Choice: FourPerspectives for the Rural Areas in the European Community. Netherlands Scientific Council forGovernment Policy. The Hague. Netherlands.

New Fann and Forest Products Task Force. 1987. New Farm and Forest Products: Responses to theChallenges and Opponunities Facing American Agriculture. A report to the Secretary ofAgriculture. June 25. 1987.

OECD (Organization for Economic Cooperation and Development). 1992. Agricultural Policies.Markets, and Trade: Monitoring and Outlook 1992. OECD, Paris. France.

OTA (Office of Technology Assessment of the U.S. Congress). 1992. Technologies to SustainTropical Forest Resources and Biological Dive~iry. OTA-F-515, U.S. Government PrintingOffice, Washington. D.C.

Parham, W. E., P. J. Durana. and A. L. Hess (eds.). 1993. Improving degraded lands: Promisingexperiences from South China. In Bishop Museum Bulletin in Botany 3, The Bishop Museum.Honolulu. Hawaii.

Response Strategies Working Group of the Intergovernmental Panel on Climate Change. 1990.Emissions Scenarios: Appendix of the &pen Group on Emissions Scenarios. U.S. EnvironmentalProtection Agency. Washington. D.C.

Smith. K. R.. and S. A. Thorneloe. 1992. Household fuels in developing countries: Global warnling,health. and energy implications. In Proceedings from the 1992 Greenhouse Gas Emissions andMitigation Research Symposium, August 18-20. 1992, sponsored by the U.S. EnvironmentalProtection Agency Air and Energy Engineering Laboratory. Washington D.C.

Soil Conse~ation Service. 1989. The Second RCA Appraisal: Soil. Water, and Related Resources onNon-Federal Land in the United States-Analysis of Condition and Trends. U.S. Department of

Agriculture.Turhollow. A. H.. and R. D. Perlack. 1991. Emissions of CO2 from energy crop production. Biomass

and Bioenergy 1.129-135.

Turnbull. J. 1993. Strategies for Achieving a Sustainable. Clean, tCZnd Cost-Effective BiomassResource. Electric Power Research Institute, Palo Alto, California.

U.S. Department of Energy. 1991. National Energy Strategy, Technical Annex 2. Integrated AnalysisSupponing the National Energy Strategy: Methodology, Assumptions. and Results. DOFlS-0086P.

Waggoner, P.E. 1994. How Much Land Can Ten Billion People Spare for Native? Council forAgricultural Science and Technology, Ames, Iowa.

Waldo M. L. 1992. California's pied piper of ~Iean air. The New York Times, Business Section,September 13,1992. .

Wald, M. L. 1994. Harder auto emission rules agreed to by eastern states. The New York Times, AI,February 2. 1994.

Williams, M. 1989. Americans and Their Forests: A Historical Geography. Cambridge Unive~ityPress, Cambridge, U.K.

Williams, R. H. 1994. The clean machine. Technology Review 97(3), 20-30.

Williams, R. H., and E. D. Larson. 1993. Advanced gasification-based power generation. InRenewable Energy: Sources for Fuel and Electricity (T. B. Johansson. H. Kelly. A. K. N. Reddy,and R. H. Williams, eds.), Island Press. Washington, D.C., 729-786.

WRI (World Resources Institute). 1992. World Resources 1992-93: A Guide to the GlobalEnvironment. Oxford University Press.

223

---

The Grand Cycles

Wyman. C. E.. R. L. Bain. N. D. Hinman. and D. J. Stevens. 1993. Ethanol and methanol from cellu-losic biomass. In Rent'Wable Energy: Sources/or Fuel and Electrici!)' (T. B. Johansson. H. Kelly.A. K. N. Reddy. and R. H. Williams. cds.). Island Press, Washington. D.C., 865-924.

Endnote for Figure 5The bar on the left represents fuel consumed in 1987 by light-duty vehicles and bycoal-fired power plants. Automobiles and light trucks, with average fueleconomies of 19.1 mpg and 12.9 mpg, respectively, consumed 103 billion gallonsof gasoline. In 1987 coal-fired power plants, operated with an average efficiencyof 32.9%, produced 1464 TWh of electricity.

The second bar shows the biomass primary energy requirements if light-dutyvehicles and coal-fired power plants at 1987 activity levels were replaced bybio-mass energy systems that are commercially available today. With present biomassgasification technology (adapted directly from coal gasification) methanol can beproduced from wood at 50% efficiency. Operated on methanol, cars and lighttrucks would have gasoline-equivalent fuel economies of 22.9 mpg and 15.5 mpg,respectively, some 20% higher than gasoline vehicles, because of the higher ther-mal efficiency of internal-combustion engines when operated on methanol(Wyman et aI., 1993), The net result is that the biomass feedstock requirements tosupport the 1987 level of light-duty vehicles would be 1/(0.5 x 1.2) = 1.67 timesthe amount of gasoline used by light-duty vehicles in 1987. The present averageefficiency of biomass power plants operating in California is about 20%, so thatthe biomass plants would require 32.9/20 = 1.65 times as much fuel to make elec-tricity as the coal plants they would displace.

The third bar shows the biomass primary energy requirements if biomass tech-nologies likely to be available in the year 2000+ time frame were used to replaceall oil used for light-duty vehicles and all coal-based power generation, at 1987activity levels. It is cost-effective to increase the average (on-the-road) fuel econ-

: omy of new cars and light trucks to aooilt 33.6 and 22.7 mpg (76% higher than in1987), respectively, if operated on gasoline, and to 40.3 and 27.2 mpg of gasoline-equivalent energy (20% higher than on gasoline), respectively, if operated onmethanol. A shift to sucp vehicles could be achieved over the next couple ofdecades. During this period it would be feasible to introduce methanol productiontechnology involving indirect biomass gaSification, for which the overall biomass-to-methanol conversion efficiency is 58% (Katofsky, 1993). With these technolo-gies biomass fuel input requirements would be (1/1.76)/(0.58 x 1.2) = 0.82 times

as large as the petroleum required in 1987. If electricity were produced from bio-mass using biomass integrated gasifier/gas turbine technology that could be intro-duced commercially in this time frame, the efficiency of power generation wouldbe 40%, nearly double that of existing biomass power plants, so that the biomassplants would require 32.9/40 = 0.82 times as much fuel to make electricity as thecoal plants they would displace.

The fourth bar shows the biomass primary energy requirements if biomass tech-

224

~ ---~

~

"(,

,.

" R. Williams: Roles for Biomass Energy

nologies likely to be available in the 2020 time frame were used to replace all oilused for light-dury vehicles and all coal-based power generation, at 1987 activirylevels. By the end of the second decade of the 21st century, biomass-derivedmethanol could be routinely used in pr~ton-exchange-membrane fuel-cell vehiclesat gasoline-equivalent fuel economies that are 2.4 times the fuel economies of

gasoline-powered intemal-combustion-engine vehicles of comparable perfor-mance (Johansson et al., 1993; Williams, 1993). With these technologies biomassfuel input requirements would be (1/1.76)/(0.64 x 2.4) = 0.408 times as large asthe petroleum required in 1987. Also, by that time, biomass integrated gasifier/fuelcell systems (using molten carbonate or solid oxide fuel cells) for stationary powergeneration could well be available with biomass-to-electriciry conversion effi-ciencies of perhaps 57% (Williams and Larson, 1993), for which fuel requirementswould be 32.9/57 = 0.577 times coal requirements for power generation in 1987.

The fifth bar shows potential U.S. biomass supplies, consisting of (1) 9 EJ peryear of plantation biomass grown on 30 million hectares of excess agriculturallands at an average productiviry of 15 dry tonnes per hectare per year and a heatingvalue of 20 GJ per dry tonne of biomass, plus (2) 6 EJ per year of those residues(urban refuse, agricultural residues, forest product industry residues) that are esti-mated to be recoverable under environmental constraints (Beyea et al., 1992).

.'

.'

..

225